Climate of the Plains.—The course of the seasons is the same in the plains. The jaded resident finds relief when the rains cease in the end of September. The days are still warm, but the skies are clear, the air dry, and the nights cool. November is rainless and in every way a pleasant month. The clouds begin to gather before Christmas, but rain often holds off till January. Pleasant though the early months of the cold weather are, they lay traps for the unwary. In October and November the daily range of temperature is very large, exceeding 30°, and the fall at sunset very sudden. Care is needed to avoid a chill and the fever that follows. Clear and dry though the air is, the blue of the skies is pale owing to a light dust haze in the upper atmosphere. For the same reason the Himalayan snows except after rain are veiled from dwellers in the plains at a distance of 30 miles from the foot-hills. The air in these months before the winter rains is wonderfully still. In the three months after Christmas the Panjáb is the pathway of a series of small storms from the west, preceded by close weather and occurring usually at intervals of a few weeks. After a day or two of wet weather the sky clears, and the storm is followed by a great drop in the temperature. The traveller who shivers after a January rain-storm finds it hard to believe that the Panjáb plain is a part of the hottest region of the Old World which stretches from the Sahára to Delhi. If he had to spend the period from May to July there he would have small doubts on the subject. The heat begins to be unpleasant in April, when hot westernly winds prevail. An occasional thunderstorm with hail relieves the strain for a little. The warmest period of the year is May and June. But the intense dry heat is healthier and to many less trying than the mugginess of the rainy season. The dust-storms which used to be common have become rarer and lighter with the spread of canal irrigation in the western Panjáb. The rains ought to break at Delhi in the end of June and at Lahore ten days or a fortnight later. There is often a long break when the climate is particularly trying. The nights are terribly hot. The outer air is then less stifling than that of the house, and there is the chance of a little comparative coolness shortly before dawn. Many therefore prefer to sleep on the roof or in the verandah. September, when the rains slacken, is a muggy, unpleasant, and unhealthy month. But in the latter half of it cooler nights give promise of a better time.

Special features of Plain Zones.—The submontane zone has the most equable and the pleasantest climate in the plains. It has a rainfall of from 30 to 40 inches, five-sevenths or more of which belongs to the monsoon period (June-September). The north-western area has a longer and colder winter and spring. In the end of December and in January the keen dry cold is distinctly trying. The figures in Statement I, for Ráwalpindí and Pesháwar, are not very characteristic of the zone as a whole. The average of the rainfall figures, 13 inches for Pesháwar and 32 for Ráwalpindí, would give a truer result. The monsoon rains come later and are much less abundant than in the submontane zone. Their influence is very feeble in the western and south-western part of the area. On the other hand the winter rains, are heavier than in any other part of the province. Delhi and Lahore represent the extreme conditions of the central and south-eastern plains. The latter is really on the edge of the dry south-western area. The eastern districts of the zone have a shorter and less severe cold weather than the western, an earlier and heavier monsoon, but scantier winter rains. The total rainfall varies from 16 to 30 inches. The south-western zone, with a rainfall of from 5 to 15 inches, is the driest part of India proper except northern Sindh and western Rájputána. Neither monsoon current affects it much. At Multán there are only about fifteen days in the whole year on which any rain falls.

CHAPTER VI

HERBS, SHRUBS, AND TREES

Affinities of Panjáb Flora.—It is hopeless to describe except in the broadest outline the flora of a tract covering an area of 250,000 square miles and ranging in altitude from a few hundred feet to a height 10,000 feet above the limit of flowering plants. The nature of the vegetation of any tract depends on rainfall and temperature, and only secondarily on soil. A desert is a tract with a dry substratum and dry air, great heat during some part of the year, and bright sunshine. The soil may be loam or sand, and as regards vegetation a sandy desert is the worst owing to the rapid drying up of the subsoil after rain. In the third of the maps appended to Schimper's Plant Geography by far the greater part of the area dealt with in this book is shown as part of the vast desert extending from the Sahára to Manchuria. Seeing that the monsoon penetrates into the province and that it is traversed by large snow-fed rivers the Panjáb, except in parts of the extreme western and south-western districts, is not a desert like the Sahára or Gobí, and Schimper recognised this by marking most of the area as semi-desert. Still the flora outside the Hills and the submontane tract is predominantly of the desert type, being xerophilous or drought-resisting. The adaptations which enable plants to survive in a tract deficient in moisture are of various kinds. The roots may be greatly developed to enable them to tap the subsoil moisture, the leaves may be reduced in size, converted into thorns, or entirely dispensed with, in order to check rapid evaporation, they may be covered with silky or felted hairs, a modification which produces the same result, or their internal tissue may be succulent or mucilaginous. In the plants of the Panjáb plains there is no difficulty in recognising these features of a drought-resisting flora. Schimper's map shows in the north-east of the area a wedge thrust in between the plains' desert and the dry elevated alpine desert cut off from the influence of the monsoon by the lofty barrier of the Inner Himálaya. This consists of two parts, monsoon forest, corresponding roughly with the Himalayan area Cis Ráví above the 5000 feet contour, and dry woodland of a semi-tropical stamp, consisting, of the adjoining foot-hills and submontane tract. This wedge is in fact treated as part of the zone, which in the map (after Drude) prefixed to Willis' Manual and Dictionary of the Flowering Plants and Ferns, is called Indo-Malayan, and which embraces the Malayan Archipelago and part of North Australia, Burma, and practically the whole of India except the Panjáb, Sindh, and Rájputána. In Drude's map the three countries last mentioned are included in a large zone called "the Mediterranean and Orient." This is a very broad classification, and in tracing the relationships of the Panjáb flora it is better to treat the desert area of North Africa, which in Tripoli and Egypt extends to the coast, apart from the Mediterranean zone. It is a familiar fact that, as we ascend lofty mountains like those of the Himálaya, we pass through belts or regions of vegetation of different types. The air steadily becomes rarer and therefore colder, especially at night, and at the higher levels there is a marked reduction in the rainfall. When the alpine region, which in the Himálaya may be taken as beginning at 11,000 feet, is reached, the plants have as a rule bigger roots, shorter stems, smaller leaves, but often larger and more brilliantly coloured flowers. These are adaptations of a drought-resisting kind.

Regions.—In this sketch it will suffice to divide the tract into six regions:

Plains1.Panjáb dry plain.
2.Salt Range and North West Plateau, from the frontier to Pabbí Hills.
3.Submontane Hills on east bank of Jhelam.
Hills4.Sub-Himálaya, 2000-5000 feet.
5.Temperate Himálaya, 5000-11,000 feet.
6.Alpine Himálaya, 11,000-16,000 feet.

Of course a flora does not fit itself into compartments, and the changes of type are gradual.

Panjáb Dry Plain.—The affinities of the flora of the Panjáb plains south of the Salt Range and the submontane tract are, especially in the west, with the desert areas of Persia, Arabia, and North Africa, though the spread of canal irrigation is modifying somewhat the character of the vegetation. The soil and climate are unsuited to the growth of large trees, but adapted to scrub jungle of a drought-resisting type, which at one time covered very large areas from the Jamna to the Jhelam. The soil on which this sparse scrub grew is a good strong loam, but the rainfall was too scanty and the water-level too deep to admit of much cultivation outside the valleys of the rivers till the labours of canal engineers carried their waters to the uplands. East of the Sutlej the Bikaner desert thrusts northwards a great wedge of sandy land which occupies a large area in Baháwalpur, Hissár, Ferozepur, and Patiála. Soil of this description is free of forest growth, and the monsoon rainfall in this part of the province is sufficient to encourage an easy, but very precarious, cultivation of autumn millets and pulses. The great Thal desert to the south of the Salt Range between the valleys of the Jhelam and the Indus has a similar soil, but the scantiness of the rainfall has confined cultivation within much narrower limits. Between the Sutlej and the Jhelam the uplands between the river valleys are known locally as Bárs. The largest of the truly indigenous trees of the Panjáb plains are the farásh (Tamarix articulata) and the thorny kíkar (Acacia Arabica). The latter yields excellent wood for agricultural implements, and fortunately it grows well in sour soils. Smaller thorny acacias are the nímbar or raunj (Acacia leucophloea) and the khair (Acacia Senegal). The dwarf tamarisk, pilchí or jhao (Tamarix dioica), grows freely in moist sandy soils near rivers. The scrub jungle consists mostly of jand (Prosopis spicigera), a near relation of the Acacias, jál or van (Salvadora oleoides), and the coral-flowered karíl or leafless caper (Capparis aphylla). All these show their desert affinities, the jand by its long root and its thorns, the jál by its small leathery leaves, and the karíl by the fact that it has managed to dispense with leaves altogether. The jand is a useful little tree, and wherever it grows the natural qualities of the soil are good. The sweetish fruit of the jál, known as pílu, is liked by the people, and in famines they will even eat the berries of the leafless caper. Other characteristic plants of the Panjáb plains are under Leguminosae, the khip (Crotalaria burhia), two Farsetias (faríd kí búti), and the jawása or camel thorn (Alhagi camelorum), practically leafless, but with very long and stout spines; under Capparidaceae several Cleomes, species of Corchorus (Tiliaceae), under Zygophyllaceae three Mediterranean genera, Tribulus, Zygophyllum, and Fagonia, under Solanaceae several Solanums and Withanias, and various salsolaceous Chenopods known as lána.